KR102149263B1 - Session management method and session management function network element - Google Patents

Abstract

Session management method and session management function network elements are provided. The session management method includes the step of learning whether a first condition is satisfied by a session management function (SMF) network element- The first condition is that the location of the first user equipment (UE) is a service area of the local area data network (LADN). (SA) includes being outside -; And when the first condition is satisfied, the SMF network element stops data transmission of the LADN packet data unit (PDU) session of the LADN, and the SMF network element maintains the resources of the LADN PDU session.

Description

Session management method and session management function network element

The embodiments of the present application relate to the field of communication, and more particularly, to a session management method and a session management function network element.

The 3rd Generation Partnership Project (3GPP) is defining the architecture of a 5th-generation (5G) system.

The core network in the architecture of the 5G system may include logical network elements such as an Access and Mobility Management Function (AMF) network element and a Session Management Function (SMF) network element.

The 5G system provides a Local Area Data Network (LADN). LADN is a network primarily deployed in scenarios such as corporate, stadium activities, and concert halls. In the current LADN, SMF network elements do not provide any solution corresponding to how to implement session management in the mobile network. A detailed implementation solution is urgently required for session management of SMF.

An embodiment of the present application provides a session management method and a session management function network element to implement session management in a local area data network (LADN) scenario.

According to a first aspect, an embodiment of the present application provides a session management method. The session management method comprises the steps of learning whether a first condition is satisfied by a session management function (SMF) network element-The first condition is that a first location of a user equipment (UE) is local Including that it is outside the service area (SA) of the local area data network (LADN) -; And when the first condition is satisfied, the SMF network element stops data transmission of the LADN packet data unit (PDU) session, and the SMF network element maintains the resource of the LADN PDU session. It includes the step of.

In an embodiment of the present application, the SMF may learn whether the first location of the UE is outside the SA of the LADN. When the UE is outside the SA of the LADN, the SMF may stop data transmission of the LADN PDU session, and the SMF maintains the resources of the LADN PDU session. Therefore, a specific solution is provided for the session management of the LADN scenario. In addition, in this solution, the UE can move in and out of the SA of the LADN to avoid high signaling overhead. When re-entry to the SA of the LADN, by maintaining the resources of the LADN PDU session so that the UE does not need to re-establish the LADN PDU session, signaling overhead is reduced and data transmission efficiency of the LADN is increased.

According to the second aspect, the embodiment of the present application further provides an SMF network element. The SMF network element, learning whether a session management function (SMF) network element satisfies a first condition-The first condition is that a first location of a user equipment (UE) is a local area data network ( LADN) includes outside the service area (SA) -; And when the first condition is satisfied, based on a policy, the SMF network element stops data transmission of the LADN packet data unit (PDU) session of the LADN, and the SMF network element is the resource of the LADN PDU session. Maintaining the; Or releasing the LADN PDU session. Here, the policy is associated with at least one of user information of the UE and identification information of the LADN.

In another embodiment of the present application, the SMF may learn whether the first location of the UE is outside the SA of the LADN. If the UE is outside the SA of the LADN, the SMF may stop data transmission of the LADN PDU session based on the policy, and the SMF maintains the resources of the LADN PDU session; Alternatively, the SMF releases the LADN PDU session. Therefore, a specific solution is provided for the session management of the LADN scenario. The SMF may manage the LADN PDU session based on the policy so that the SMF can implement different session management functions using a specific configuration for the policy. Accordingly, flexible management of the LADN PDU session can be further implemented using this solution.

With reference to the first aspect or the second aspect, in a first possible embodiment of the first aspect or the second aspect, the step of learning whether the session management function (SMF) network element satisfies the first condition comprises: An SMF network element obtaining a first location of the UE, and determining, based on the first location of the UE, whether the UE is outside the SA of the LADN; Or acquiring a notification message including whether the SMF network element is outside the SA of the LADN, and learning whether the UE is outside the SA of the LADN based on the notification message. The SMF network element may obtain a first location of the UE and, based on the first location, determine whether the UE is outside the SA of the LADN; Alternatively, by parsing the notification message, it is possible to learn whether the UE is outside the SA of the LADN. Accordingly, the SMF network element may learn whether the UE satisfies the first condition.

With reference to the first aspect or the second aspect or the first possible embodiment, in the second possible embodiment of the first aspect or the second aspect, the session management method, wherein the SMF network element determines the state of the LADN PDU session. Further comprising the step of obtaining. Here, the first condition further includes that the LADN PDU session is in an active state. The above-described session management is performed when the first location of the UE is outside the SA of the LADN and the LADN PDU session is in the active state so that session management for the LADN PDU session in the active state can be implemented. Can be.

In a third possible embodiment of the first or second aspect, with reference to the first aspect or the second aspect or the possible first or second embodiment, data transmission of the LADN PDU session of the local area data network (LADN) The step of stopping may include: notifying, by the SMF network element, a user plane function (UPF) network element to buffer or discard received downlink data; Or when the SMF network element receives a downlink data notification from the UPF network element, maintaining, by the SMF network element, the state of the LADN PDU session in an inactive state. When the UE is in the SA of the LADN, the UPF network element may transmit the buffered downlink data to the UE when recovering the LADN PDU session. Therefore, the downlink data transmitted by the DN to the UE is not lost. The SMF network element may stop data transmission of the LADN PDU session by maintaining the inactive state of the LADN PDU session.

With reference to the third possible embodiment of the first aspect or the second aspect, in a fourth possible embodiment of the first or second aspect, the SMF network element is configured to buffer or discard the received downlink data. Notifying a plane function (UPF) network element includes the step of notifying the UPF network element to activate a timer, and buffer or discard the received downlink data before the timer expires. and; The session management method includes: when the UPF network element receives downlink data after the timer expires, the SMF network element receives a downlink data notification from the UPF network element; And triggering, by the SMF network element, establishment of transmission resources of the LADN PDU session in response to the received downlink data notification. After the timer expires, the UPF network element may recover from transmitting the downlink data notification to the SMF so that the SMF network element can trigger establishment of the transmission resource of the LADN PDU session. Establishing the transmission resource of the LADN PDU session means that the LADN PDU session enters the active state to implement adaptive recovery of the state of the LADN PDU session.

With reference to the third possible embodiment of the first aspect or the second aspect, in a fifth possible embodiment of the first aspect or the second aspect, the SMF network element is configured to buffer or discard the received downlink data. The step of notifying a flat function (UPF) network element may include: the SMF network element activates a timer, and the UPF buffers or discards the received downlink data when the UPF network element receives the downlink data. Notifying the network element; The session management method includes, after the timer expires, the SMF network element notifies the UPF network element to transmit a downlink data notification to the SMF network element when the UPF network element receives downlink data. It further includes steps. After the timer expires, the SMF network element uses the timer to complete automatic switching between various types of session management, so that when the UPF network element receives the downlink data Inform the UPF network element to transmit the downlink data notification.

With reference to the third possible embodiment of the first aspect or the second aspect, in a sixth possible embodiment of the first aspect or the second aspect, when the SMF network element receives a downlink data notification from the UPF network element. , The SMF network element maintaining the state of the LADN PDU session in an inactive state, the SMF network element activates a timer, and before the timer expires, the SMF network element is the downlink from the UPF network element. Upon receiving a data notification, the SMF network element maintaining a state of the LADN PDU session in the inactive state; The session management method comprises, after the timer expires, when the SMF network element receives the downlink data notification from the UPF network element, the SMF network element triggers establishment of transmission resources of the LADN PDU session. It further includes steps. Using the timer set by the SMF network element, the SMF network element can recover from triggering the establishment of the transmission resource of the LADN PDU session after the timer expires, that is, the SMF network element By triggering the LADN PDU session to enter the active state, adaptive restoration of the state of the LADN PDU session is implemented.

With reference to the first or second or third or fourth or fifth or sixth possible embodiment of the first aspect or the second aspect, in a seventh possible embodiment of the first or second aspect, the LADN PDU Maintaining the resources of the session may include: maintaining, by the SMF network element, a radio access network (RAN) resource and a UPF network element resource of the LADN PDU session; Or, by the SMF network element, releasing RAN resources of the LADN PDU session, and maintaining UPF network element resources of the LADN PDU session; Or the SMF network element releasing the RAN resource and the UPF network element resource of the LADN PDU session, and the SMF network element maintaining the SMF network element resource. When re-entry to the SA of the LADN, resources of the LADN PDU session are maintained so that the UE does not need to re-establish the LADN PDU session, thereby reducing signaling overhead and increasing the data transmission efficiency of the LADN.

With reference to the first aspect or the seventh possible embodiment of the second aspect, in a possible eighth embodiment of the first aspect or the second aspect, the step of the SMF network element releasing the RAN resource of the LADN PDU session, When the RAN transmits uplink data to the UPF network element, the UPF network element returns error information to the RAN, and the RAN can release the RAN resource based on the error information, the SMF Informing the RAN to release the RAN resource by the network element through the AMF network element; Or notifying the UPF network element so that the SMF network element releases the UPF network element resource. The RAN may release the RAN resource based on the notification of the SMF network element, or the RAN may release the RAN resource based on the error information from the UPF network element. The RAN releases the RAN resources so that data transmission of the LADN PDU session can be stopped.

A possible ninth implementation of the first or second aspect, with reference to the first or second or third or fourth or fifth or sixth or seventh or eighth possible embodiment of the first or second aspect. In the form, the session management method includes the step of learning whether the SMF network element satisfies a second condition-The second condition is that the second position obtained after the UE moves is in the SA of the LADN. Contains -; And when the second condition is satisfied, the SMF network element recovering data transmission of the LADN PDU session. When the location of the second UE is in the SA of the LADN, the SMF network element may recover data transmission of the LADN PDU session so that the LADN can continue to provide network services for the UE.

With reference to the possible first or second or third or fourth or fifth or sixth or seventh or eighth or ninth embodiment of the second aspect, in the tenth possible embodiment of the second aspect, the session The management method includes: obtaining, by the SMF network element, the policy from a local policy of the SMF network element; Or obtaining, by the SMF network element, the policy from a policy control function (PCF) network element. The policy used by the SMF network element is stored in the local policy of the SMF network element or the PCF network element side so that the SMF network element can manage the LADN PDU session based on the obtained policy. Can be saved.

With reference to the possible first or second or third or fourth or fifth or sixth or seventh or eighth or ninth or tenth embodiment of the first or second aspect, the first aspect or the second In an eleventh possible embodiment of the aspect, the step of obtaining the first position of the UE by the SMF network element comprises: when the UE is in an idle state, the SMF network element notifies the downlink data from the UPF network element Receiving, and triggering the access and mobility management function (AMF) network element to call the UE based on the downlink data notification by the SMF network element; And when the UE initiates a service request in response to the call, obtaining, by the SMF network element, the first location of the UE from the RAN using the AMF network element. Or the SMF network element subscribes to the location information of the UE from the AMF network element, and the SMF network element receives the first location from the AMF network element.

The first aspect, with reference to the possible first or second or third or fourth or fifth or sixth or seventh or eighth or ninth or tenth or eleventh embodiment of the first or second aspect Or in a twelfth possible embodiment of the second aspect, the session management method further comprises the step of obtaining, by the SMF network element, information about the SA of the LADN from the PCF network element or the AMF network element. In order to allow the SMF network element to determine whether the UE is outside the SA using the obtained information on the SA and the location information of the UE, the SMF network element as information about the SA of the LADN The information used by the PCF network element or the AMF network element is obtained.

According to a third aspect, an embodiment of the present application further provides a session management function (SMF) network element. The SMF network element is a condition learning module configured to learn whether a first condition is satisfied.- The first condition is that the first location of a user equipment (UE) is a service area of a local area data network (LADN) ( SA) includes being outside -; And a processing module configured to stop data transmission of the LADN packet data unit (PDU) session of the LADN and maintain resources of the LADN PDU session when the first condition is satisfied.

In an embodiment of the present application, the SMF may learn whether the first location of the UE is outside the SA of the LADN. When the UE is outside the SA of the LADN, the SMF may stop data transmission of the LADN PDU session, and the SMF maintains the resources of the LADN PDU session. Therefore, a specific solution is provided for the session management of the LADN scenario. In addition, in this solution, the UE can move in and out of the SA of the LADN to avoid high signaling overhead. When re-entry to the SA of the LADN, resources of the LADN PDU session are maintained so that the UE does not need to re-establish the LADN PDU session, thereby reducing signaling overhead and increasing the data transmission efficiency of the LADN.

According to a fourth aspect, an embodiment of the present application further provides a session management function (SMF) network element. The SMF network element is a condition learning module configured to learn whether a first condition is satisfied.- The first condition is that the first location of a user equipment (UE) is a service area of a local area data network (LADN) ( SA) includes being outside -; And if the first condition is satisfied, based on a policy, stop data transmission of the LADN packet data unit (PDU) session of the local area data network (LADN), and maintain the resource of the LADN PDU session, or And a processing module configured to release the LADN PDU session. Here, the policy is associated with at least one of user information of the UE and identification information of the LADN.

In another embodiment of the present application, the SMF may learn whether the first location of the UE is outside the SA of the LADN. If the UE is outside the SA of the LADN, the SMF may stop data transmission of the LADN PDU session based on the policy, and the SMF maintains the resources of the LADN PDU session; Alternatively, the SMF releases the LADN PDU session. Therefore, a specific solution is provided for the session management of the LADN scenario. The SMF may manage the LADN PDU session based on the policy so that the SMF can implement different session management functions using a specific configuration for the policy. Accordingly, flexible management of the LADN PDU session can be further implemented using this solution.

In the third or fourth aspect of the present application, the configuration module of the SMF network element may additionally perform the steps described in the first or second aspects and possible various embodiments. For details, refer to the foregoing description in the first or second aspect and possible various embodiments.

According to a fifth aspect, an embodiment of the present application further provides a session management function (SMF) network element. The SMF includes a processor, memory, transmitter, and receiver; The processor, the transmitter, the receiver, and the memory communicate with each other using a bus; The transmitter is configured to transmit data, and the receiver is configured to receive data; The memory is configured to store instructions; The processor is configured to execute the instruction in the memory to thereby perform the session management method according to either the first aspect or the second aspect.

A sixth aspect of the present application provides a computer-readable storage medium. The computer-readable storage medium stores an instruction, and when the instruction is executed on a computer, the computer performs a session management method according to the above-described aspect.

A seventh aspect of the present application provides a computer program product including instructions, and when the computer program product is executed on a computer, the computer performs a session management method according to the above-described aspect.

1A is a diagram schematically illustrating a system architecture of a 5G system to which a session management method according to an embodiment of the present application is applied.
1B is a diagram schematically illustrating an LADN application scenario according to an embodiment of the present application.
2 is a block flow diagram schematically illustrating a session management method according to an embodiment of the present application.
3 is a block flow diagram schematically illustrating another session management method according to an embodiment of the present application.
4 is a schematic flowchart illustrating an interaction between a plurality of network elements in a session management method in a handover procedure according to an embodiment of the present application.
5 is a schematic flowchart illustrating an interaction between a plurality of network elements in a scenario of releasing RAN resources according to an embodiment of the present application.
6 is a schematic flowchart showing another interaction between a plurality of network elements in a session management method in a handover procedure according to an embodiment of the present application.
7 is a schematic flowchart showing an interaction between a plurality of network elements in a method for managing a session in a calling procedure according to an embodiment of the present application.
8A is a structural diagram schematically showing the configuration of an SMF network element according to an embodiment of the present application.
8B is a structural diagram schematically showing the configuration of another SMF network element according to an embodiment of the present application.
8C is a structural diagram schematically showing the configuration of another SMF network element according to an embodiment of the present application.
8D is a structural diagram schematically showing the configuration of another SMF network element according to an embodiment of the present application.
9 is a structural diagram schematically showing the configuration of another SMF network element according to an embodiment of the present application.

An embodiment of the present application provides a session management method and a session management function network element to implement session management in a local area data network (LADN) scenario.

Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings.

In the specification, claims, and accompanying drawings of the present application, terms such as "first" and "second" are used to distinguish similar objects, but do not necessarily indicate a specific order or sequence. Terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that this is only an identification method used when objects having the same properties are described in the embodiments of the present application. In addition, a process, method, system, product, or device comprising a series of units is not necessarily limited to such units, and is not explicitly listed, or other processes specific to such a process, method, system, product, or device. In order to be able to include a unit, terms such as "include," and other variations of the term are intended to encompass, without limitation, including.

The session management method provided in the embodiment of the present application may be applied to a session management function (SMF) network element or other network device having a session management function in a 5G system. Referring to FIG. 1A, FIG. 1A is a schematic diagram of a system architecture of a 5G system to which a session management method according to an embodiment of the present application is applied. The architecture of the 5G system is divided into two parts, an access network and a core network. The access network is used to implement radio access-related functions, and the access network includes a radio accessing network (RAN). The core network is mainly composed of several core logical network elements, namely AMF network elements, SMF network elements, User Plane Function (UPF) network elements, Policy Control Function (PCF) network elements, and integrated data management. Unified Data Management, UDM) network element, and Application Function (AF) network element.

The AMF network element is primarily responsible for mobility management in the mobile network, eg registration of user location updates of users in the network, and user handover.

The SMF network element is mainly responsible for session management in the mobile network. For example, specific functions of the SMF network element may include allocating an Internet Protocol (IP) address to a user, and selecting a UPF network element that provides a packet forwarding function.

The UPF network element is primarily responsible for processing user packets, for example forwarding and billing.

The PCF network element is responsible for providing policies such as a slicing selection policy and a quality of service (QoS) policy to the AMF network element and the SMF network element.

The UDM network element is configured to store user subscription information.

The 5G system may further include an authentication server function (AUSF) network element, a user equipment (UE), and a data network (DN).

The UE is a network terminal device such as a mobile phone or a terminal device of the Internet of Things. In order for the UE to access a data network (DN) using a LADN PDU session, the UE is a LADN packet data unit between the UE and the RAN, between the RAN and the UPF network element, and between the UPF network element and the DN. , PDU) Establish a session. The LADN PDU session may include an activation state and a deactivation state. In the case of a session of the UE, when there is a user plane connection between the UE and the RAN, and a user plane connection between the RAN and the UPF network element, that is, when the RAN and UPF network elements have resources related to the LADN PDU session, The session is in an active state. There is a user plane connection between the UE and the RAN and between the RAN and the UPF network element, but the SMF network element and the UPF network element have some session context, such as the UE's Internet Protocol (IP) address and session ID. Save it. In other words, when the RAN does not have any session resources but the UPF network element has session resources, the LADN PDU session is in an inactive state. When there is a non-access layer (Non Access Stratum, NAS) signaling connection between the UE and the AMF network element, the UE is in a connected (CONNECTED) state. If the UE is already registered in the network but there is no NAS signaling connection between the UE and the AMF network element, the UE is in an IDLE state.

Referring to FIG. 1B, FIG. 1B is a diagram schematically illustrating an LADN application scenario according to an embodiment of the present application. LADN has a characteristic that the UE can access the LADN only when the UE is in a service area (SA) of the LADN. As shown in FIG. 1B, the SA of LADN includes three tracking areas (TA), that is, TA 1, TA 2, and TA 3. Since RAN 1 is within the coverage of the SA of LADN, when the UE moves to the coverage of RAN 1, the UE can establish a session for accessing the LADN. When the UE continues to move and moves to the coverage of RAN 2, the UE cannot access the LADN using RAN 2 because RAN 2 exceeds the coverage of the SA of LADN.

No solution corresponding to how the SMF implements session management in the LADN-based mobile network shown in Fig. 1B is provided in the prior art. In the embodiment of the present application, the SMF may perform the following session management solution.

2 is a diagram illustrating a session management method according to an embodiment of the present application. The session management method may include the following steps.

201. The SMF network element learns whether the first condition is satisfied. Here, the first condition includes that the location of the first UE is outside the SA of the LADN.

In this embodiment of the present application, the SMF network element may be configured to manage the LADN PDU session. In LADN, radio-side network elements include UE and RAN. The SMF network element first learns whether the current location of the UE is outside the SA of the LADN. For convenience of explanation, the current location of the UE is defined as a “first location”, and that the first location of the UE is outside the SA of the LADN is defined as the “first condition”. Specifically, if the first condition is satisfied, the first location of the UE is outside the SA of the LADN. If the first condition is not satisfied, the first location of the UE is in the SA of the LADN.

Learning whether the SMF network element is satisfied with the first condition in step 201 may be implemented by the SMF network element that acquires the first location of the UE, and based on the first location, whether the UE is outside the SA of the LADN It should be noted that it determines whether or not. Alternatively, when the LADN PDU session is in an inactive state, in step 201, the SMF network element may obtain a notification message including whether the UE is outside the SA of the LADN, and the SMF network element is based on the notification message. , Learn that the first location of the UE is outside the SA of the LADN. The LADN PDU session in the inactive state includes at least the following two cases: (1) the UE is in the connected state, the LADN PDU session is in the inactive state, and (2) the UE is in the idle state. Are doing.

202. If the first condition is satisfied, the SMF network element stops data transmission of the LADN PDU session of the LADN, and the SMF network element maintains the resources of the LADN PDU session.

In this embodiment of the present application, the SMF network element may learn whether the first condition is satisfied, and if the first condition is satisfied, step 202 is performed. The SMF network element can manage the LADN PDU session in a plurality of ways. For example, the SMF network element may stop data transmission of the LADN PDU session of the LADN, and the SMF network element maintains the resources of the LADN PDU session. When the SMF network element stops data transmission of the LADN PDU session of the LADN, it means that the SMF stops data transmission of the LADN PDU session, and the SMF can maintain the resources of the LADN PDU session. In other words, the resource of the LADN PDU session still exists, and only data transmission of the LADN PDU session is stopped. In this embodiment of the present application, the SMF network element determines whether the UE is outside the SA of the LADN, based on the first location of the UE, so that the SMF network element can determine whether the first condition is satisfied. For example, as shown in FIG. 1B, when the UE is connected to RAN 1, the current location of the UE is in the SA of the LADN. If the UE is connected to RAN 2 after the UE moves, the location of the UE is outside the SA of the LADN. Specifically, the first condition includes that the first location of the UE is outside the SA of the LADN. When the first location of the UE is outside the SA of the LADN, the LADN cannot provide network services for the UE.

For example, it can be seen from the above description of the LADN scenario, in the prior art, in the case of a connected UE, high signaling overhead is caused when the UE frequently enters and exits the SA of the LADN. Signaling is used to terminate or re-establish a LADN PDU session. For a UE in an idle state, when downlink data (DL) arrives for a LADN PDU session, the UE needs to be called frequently, thus increasing overhead. Based on the above-described solution of the present application, the SMF network element can stop data transmission of the LADN PDU session, and the SMF network element maintains the resources of the LADN PDU session. Therefore, a specific solution is provided for session management in the LADN scenario. In addition, in this solution, high signaling overhead caused by the UE moving in and out of the SA of the LADN can be avoided. When re-entry to the SA of LADN, the resources of the LADN PDU session are maintained so that the UE does not need to re-establish the LADN PDU session, thereby reducing signaling overhead and increasing the data transmission efficiency of the LADN.

3 is a diagram illustrating a session management method according to an embodiment of the present application. The session management method may include the following steps.

301. The SMF network element learns whether the first condition is satisfied. Here, the first condition includes that the first location of the user equipment (UE) is outside the service area (SA) of the local area data network (LADN).

In this embodiment of the present application, the SMF network element may be configured to manage the LADN PDU session. In LADN, the radio side network element includes the UE and the RAN. The SMF network element first learns whether the current location of the UE is outside the SA of the LADN. Learning whether the SMF network element is satisfied with the first condition in step 301 means that the SMF network element acquires a first location of the UE, and based on the first location, determines whether the UE is outside the SA of the LADN. Can be implemented by Alternatively, when the LADN PDU session is in an inactive state, in step 301, the SMF network element may obtain a notification message including whether the UE is outside the SA of the LADN, and the SMF network element is based on the notification message. , Learn that the first location of the UE is outside the SA of the LADN. The LADN PDU session in the inactive state includes at least the following two cases: (1) the UE is in the connected state, the LADN PDU session is in the inactive state, and (2) the UE is in the idle state. Are doing.

302. If the first condition is satisfied, the SMF network element, based on a policy associated with at least one of the user information of the UE and the identification information of the LADN, stops data transmission of the LADN PDU session, and the resources of the LADN PDU session To keep; Or, release the LADN PDU session.

In this embodiment of the present application, the SMF network element may learn whether the first condition is satisfied, and if the first condition is satisfied, step 302 is performed. The SMF network element may manage the LADN PDU session in a plurality of ways based on the policy.

In step 302, the SMF network element, based on the policy, the SMF network element stops data transmission of the LADN PDU session, and maintains the resources of the LADN PDU session based on the policy; Alternatively, the SMF network element selects to perform any one of the operations of releasing the LADN PDU session based on the policy.

For a method of stopping data transmission of the LADN PDU session and maintaining the resources of the LADN PDU session, refer to the above description of step 202. That the SMF network element releases the LADN PDU session means that the SMF releases the LADN PDU session connection. Releasing the LADN PDU session may include releasing RAN resources, releasing UPF network element resources, and releasing SMF network element resources.

For example, it can be seen from the above description of the LADN scenario, in the prior art, in the case of a connected UE, when the UE frequently enters and exits the SA of the LADN, high signaling overhead is caused. Signaling is used to disconnect or re-establish the LADN PDU session. In the case of a UE in an idle state, when downlink (DL) data arrives for a LADN PDU session, the UE needs to be called frequently, and thus overhead is increased. In this embodiment of the present application, the SMF network element may stop data transmission of the LADN PDU session, and the SMF network element maintains the resources of the LADN PDU session based on the policy or the LADN PDU based on the SMF network element policy. Release the session. Therefore, a specific solution is provided for session management in the LADN scenario. The SMF network element may manage the LADN PDU session based on the policy so that the SMF network element can perform different session management functions using a specific configuration for the policy. Thus, flexible management of LADN PDU sessions can be additionally implemented using this solution.

In some embodiments of the present application, prior to step 202 or 302, the session management method provided in this embodiment of the present application further includes the following steps.

A1. The SMF network element acquires the state of the LADN PDU session.

It can be seen from the above description that the state of the LADN PDU session includes an active state and an inactive state. In an implementation scenario in which the SMF network element performs step A1, the first condition in step 202 or 302 further includes that the LADN PDU session is in an active state. Taking step 202 as an example, when the first location of the UE is outside the SA of the LADN and the LADN PDU session is in the active state, step 202 is performed, so that session management for the LADN PDU session in the active state can be implemented. .

In some embodiments of the present application, in step 202 or step 302 above, the SMF network element stopping data transmission of the LADN PDU session of the LADN includes the following steps.

B1. The SMF network element notifies the UPF network element to buffer or discard the received downlink data; or

B2. When the SMF network element receives the downlink data notification from the UPF network element, the SMF network element maintains the state of the LADN PDU session in an inactive state.

In step B1, when the UPF network element receives downlink data, the UPF network element buffers or discards the downlink data based on the notification of the SMF network element, thereby stopping data transmission of the LADN PDU session. In this way, a solution is provided for the case that the UE cannot use the LADN when the first location of the UE is outside the SA of the LADN. For example, when the UE is in the SA of the LADN and the LADN PDU session is restored, the UPF network element may transmit buffered downlink data to the UE. Therefore, downlink data transmitted by the DN to the UE is not lost. For another example, when the UPF network element receives the downlink data, the downlink data is buffered or discarded. In other words, the UPF network element does not forward downlink data to the UE in order to stop transmission of downlink data. In step B2, when the UPF network element receives downlink data from the DN, the UPF network element transmits a downlink data notification to the SMF network element, so that the SMF network element maintains the state of the LADN PDU session in an inactive state. When the LADN PDU session is in an inactive state, data transmission cannot be performed. Accordingly, the SMF network element may stop data transmission of the LADN PDU session by maintaining the inactive state of the LADN PDU session.

Further, in some embodiments of the present application, the SMF network element notifying the UPF network element to buffer or discard received downlink data in step B1 includes the following steps.

B11. The SMF network element activates the timer and informs the UPF network element to buffer or discard the received downlink data before the timer expires.

In the scenario of performing step B11, the session management method provided in this embodiment of the present application further includes the following steps.

B3. When the UPF network element receives downlink data after the timer expires, the SMF network element receives a downlink data notification from the UPF network element.

B4. The SMF network element triggers the LADN PDU session to enter the active state in response to the received downlink data notification.

In other words, the SMF network element notifies the UPF network element to activate the timer and buffer or discard downlink data before the timer expires. When the UPF network element receives downlink data after the timer expires, the UPF network element transmits a downlink data notification to the SMF network element, thereby triggering a LADN PDU session in order for the SMF network element to enter the active state. Using the timer set by the UPF network element, the UPF network element recovers from transmitting the downlink data notification to the SMF after the timer expires, so that the SMF network element can trigger the establishment of the transmission resource of the LADN PDU session. . The establishment of the transmission resource of the LADN PDU session means that the LADN PDU session enters the active state to implement adaptive restoration of the state of the LADN PDU session.

Further, in some other embodiments of the present application, the SMF network element notifying the UPF network element to buffer or discard the received downlink data in step B1 includes the following steps.

B12. Activates the SMF network element timer and informs the UPF network element to buffer or discard the received downlink data when the UPF network element receives the downlink data.

In the scenario of performing step B12, the session management method provided in some embodiments of the present application further includes the following steps.

B5. After the timer expires, when the UPF network element receives downlink data, the SMF network element notifies the UPF network element to notify the downlink data notification to the SMF network element.

In some embodiments of the present application, when the SMF network element receives a downlink data notification from the UPF network element in step B2, the SMF network element maintains the state of the LADN PDU session in an inactive state, including the following steps: .

B21. Before the timer expires, when the SMF network element receives a downlink data notification from the UPF network element, the SMF network element maintains the state of the LADN PDU session in an inactive state.

In the scenario of performing step B21, the session management method provided in this embodiment of the present application further includes the following steps.

B6. After the timer expires, when the SMF network element receives a downlink data notification from the UPF network element, the SMF network element triggers establishment of a transmission resource of the LADN PDU session.

In other words, when the UPF network element receives downlink data, the SMF network element activates the timer and informs the UPF network element to buffer or discard the downlink data. Before the timer expires, when receiving a downlink data notification from the UPF network element, the SMF network element does not trigger the LADN PDU session to enter the active state. After the timer expires, the SMF network element receives a downlink data notification from the UPF network element. Using the timer set by the SMF network element, the SMF network element can recover from triggering the establishment of the transmission resource of the LADN PDU session after the timer expires. In other words, the SMF network element implements adaptive restoration of the state of the LADN PDU session by triggering the LADN PDU session to enter the active state.

In some embodiments of the present application, the above-described step 202 or step 302 in which the SMF network element maintains the resources of the LADN PDU session includes the following steps.

C1. The SMF network element maintains radio access network (RAN) resources and UPF network element resources for the LADN PDU session; or

C2. The SMF network element releases the RAN resource for the LADN PDU session, but maintains the UPF network element resource for the LADN PDU session; or

C3. The SMF network element releases RAN resources and UPF network element resources for the LADN PDU session, but maintains the SMF network element resources for the LADN PDU session.

In the above-described embodiment of the present application, resources of the LADN PDU session may include, specifically, RAN resources, UPF network element resources, and SMF network element resources. Specifically, that the SMF network element maintains the resource of the LADN PDU session may be maintaining at least one of the RAN resource, the UPF network element resource, and the SMF network element resource. RAN resources include radio resources between RAN and UE, tunnel connection between RAN and UPF, and quality of service (QoS) of a session. The UPF network element resource includes a tunnel connection between the RAN and the UPF network element, a session identifier, a quality of service (QoS) of a session, and an IP address of a UE corresponding to the session. The SMF network element resource includes a session identifier, a session state, and a UPF identifier. The resource of the LADN PDU session is maintained using the above implementation, thereby avoiding high signaling overhead due to frequent movements of the UE entering and leaving the SA of the LADN. When re-entry to the LADN SA, the resources of the LADN PDU session are maintained so that the UE does not need to re-establish the LADN PDU session, thereby reducing signaling overhead and increasing the data transmission efficiency of the LADN.

In addition, in step C1 or step C2, the SMF network element releases the RAN resource of the LADN PDU session,

When the RAN transmits uplink data to the UPF network element, the UPF network element returns error information to the RAN, and the SMF network element through the AMF network element so that the RAN can release the RAN resource based on the error information. , Notifying the RAN to release RAN resources; Or notifying the UPF network element to release the UPF network element resource by the SMF network element.

The RAN may release the RAN resource based on the notification of the SMF network element, or the RAN may release the RAN resource based on the error information transmitted by the UPF network element. The RAN releases RAN resources so that data transmission of the LADN PDU session can be stopped.

In some embodiments of the present application, in an implementation scenario in which steps 201 and 202 are performed or in an implementation scenario in which steps 301 and 302 are performed, the session management method provided in the present embodiment of the present application further includes the following steps: do.

D1. The SMF network element learns whether the second condition is satisfied. Here, the second condition includes that the second location obtained after the UE moves is in the SA of the LADN.

D2. When the second condition is satisfied, the SMF network element recovers data transmission of the LADN PDU session.

The UE can move in real time. For example, the UE moves from a first location to a second location. The SMF network element learns whether the second condition is satisfied. For example, the SMF network element acquires a second location obtained after the UE moves so that the SMF network element can determine whether the second condition is satisfied. If the second condition is satisfied, step D2 is performed. It can be seen from the description from steps 202 and 302 that the SMF network element stops data transmission of the LADN's LADN PDU session when the UE is in the first location. In this embodiment of the present application, the SMF network element learns whether the UE is outside the SA of the LADN so that the SMF network element can learn whether the second condition is satisfied. For example, as shown in FIG. 1B, when the UE is connected to RAN 1, the current location of the UE is in the SA of the LADN. When the UE is connected to RAN 2, after the UE moves, the location of the UE is outside the SA of the LADN. Specifically, the second condition includes that the location of the second UE is in the SA of the LADN. When the location of the second UE is within the SA of the LADN, the SMF network element may recover data transmission of the LADN PDU session so that the LADN can continue to provide network services for the UE.

In some embodiments of the present application, in an implementation scenario of performing steps 301 and 302, the session management method provided in this embodiment of the present application further includes the following steps.

E1. The SMF network element obtains a policy from the local policy of the SMF network element; or

E2. The SMF network element obtains the policy from the PCF network element.

The policy used by the SMF network element in step 302 may be stored in the local policy of the SMF network element. For example, the SMF network element obtains the policy used in step 302 from local memory. The SMF network element may alternatively obtain the policy used in step 302 from the PCF network element. The PCF network element may store the policy, and the PCF network element may provide a policy for the SMF network element so that the SMF network element can manage the LADN PDU session based on the acquired policy.

In some embodiments of the present application, in an implementation scenario in which steps 201 and 202 or steps 301 and 302 are performed, learning whether the network element in step 201 or in step 301 satisfies the first condition means that the following Includes steps.

F1. The SMF network element obtains the first location of the UE, and, based on the first location of the UE, determines whether the UE is outside the SA of the LADN; or

F2. The SMF network element acquires a notification message including whether the UE is outside the SA of the LADN, and learns whether the UE is outside the SA of the LADN based on the notification message.

That the SMF network element learns whether the first condition is satisfied may mean that the SMF network element acquires a first location of the UE and, based on the first location, determines whether the UE is outside the SA of the LADN. . Alternatively, when the LADN PDU session is in an inactive state, the SMF network element may obtain a notification message including whether the UE is outside the SA of the LADN, and the SMF network element may obtain a notification message based on the notification message. It learns that location 1 is outside the SA of LADN. In the scenario shown in step F2, for example, the SMF network element subscribes to a notification message including whether the UE is outside the SA of the LADN from the AMF network element. When the AMF network element finds that the UE is outside the SA of the LADN, the SMF network element receives a notification message from the AMF network element. The AMF network element may determine whether the UE is outside the SA of the LADN based on the location information of the UE and the SA of the LADN.

In addition, in step F1, that the SMF network element acquires the first location of the UE may specifically include the following steps.

F11. When the UE is in an idle state, the SMF network element receives a downlink data notification from the UPF network element, and the SMF network element triggers the AMF network element to call the UE based on the downlink data notification; When the UE initiates a service request in response to the call, the SMF network element obtains the first location of the UE from the RAN through the AMF network element, and based on the first location, determines whether the UE is outside the SA of the LADN do or; or

F12. The SMF network element subscribes to the location information of the UE from the AMF network element, the SMF network element receives the first location from the AMF network element, and based on the first location, determines whether the UE is outside the SA of the LADN.

In the scenario shown in step F11, the SMF network element triggers the AMF network element based on the downlink data notification, the AMF network element calls the UE in the idle state, and the UE initiates a service request procedure in response to the call. do. In the above-described service request procedure, the RAN transmits the first location of the UE through the AMF network element to the SMF network element, and the SMF network element determines whether the UE is outside the SA of the LADN based on the first location.

In the scenario shown in step F12, the SMF subscribes to the location information of the UE from the AMF. When the AMF network element finds that the location of the UE has changed, the SMF network element receives the first location from the AMF network element, and the SMF network element determines whether the UE is outside the SA of the LADN based on the first location. .

In some embodiments of the present application, in an implementation scenario of performing steps 201 and 202 or steps 301 and 302, the session management method provided in this embodiment of the present application further includes the following steps.

G1. The SMF network element acquires information about the SA of the LADN from the PCF network element or the AMF network element.

Information used by the SMF network element as information about the SA of LADN is obtained from the PCF network element or the AMF network element. For example, the PCF network element stores information about the SA of the LADN, and the PCF network element transmits information about the SA of the LADN to the SMF network element. For another example, the AMF network element stores information about the SA of the LADN, so that the SMF network element can determine whether the UE is outside the SA of the LADN based on the SA of the LADN and the first location of the UE, The AMF network element transmits information on the SA of the LADN to the SMF network element. Of course, in some embodiments of the present application, the SMF network element may alternatively obtain information about the SA by local configuration. The specific implementation depends on the application scenario. This is not limited here.

In some embodiments of the present application, in an implementation scenario performing step 302, a policy used by the SMF network element will be described below as an example. The policy used by the SMF network element may include at least the following four types of policies.

Type-1 policy: The SMF network element maintains the RAN resource and the UPF network element resource for the LADN PDU session, and the SMF network element notifies the UPF network element to buffer or discard the received downlink data.

Type-2 policy (LADN PDU session enters the first state) The SMF network element releases RAN resources for the LADN PDU session, but maintains the UPF network element resource for the LADN PDU session, and the SMF network element is received. Notifies the UPF network element to buffer or discard link data.

Type-3 policy (LADN PDU session enters the second state) The SMF network element releases the RAN resource for the LADN PDU session, but maintains the UPF network element resource for the LADN PDU session, and the SMF network element is the UPF network element. When receiving a downlink data notification from, the SMF network element maintains the state of the LADN PDU session in an inactive state. In other words, when receiving the downlink data notification, the SMF does not recover the active state by triggering the LADN PDU session.

Type-4 policy: The SMF network element releases the LADN PDU session. In other words, the SMF network element releases the RAN resource and the UPF resource.

Type-1 policy, type-2 policy, and type-3 policy can be summarized as follows. SMF stops data transmission of the LADN PDU session and maintains the resources for the LADN PDU session. For details, refer to the detailed description of the foregoing embodiments.

In order to better understand and implement the above-described solutions of the embodiments of the present application, a specific description is provided taking a corresponding application scenario as an example.

In a subsequent embodiment of the present application, an example in which the UE moves and the SMF network element processes the LADN PDU session based on the policy is used for explanation. The policy may be a local policy, or may be a policy from a PCF network element. In a subsequent embodiment, the SMF network element may also be simply referred to as SMF. By analogy, the PCF network element is referred to as PCF for short, and the AMF network element is referred to as AMF for short.

Policies used by the SMF include a type-1 policy to a type-4 policy.

In the exemplary scenario of the present application, there are at least two ways of releasing RAN resources and are as follows.

RAN resource release method 1: UPF resource is released. When transmitting uplink data to the UPF, the RAN receives error information returned by the UPF so that the RAN resources can be released.

RAN resource release method 2: SMF notifies the RAN to release RAN resources.

In some embodiments of the present application, the SMF or PCF determines a policy among the type-1 policy to type 4 to be used based on the LADN name (Local Area Data Network Name, LADNN) and/or user information. For example, the user information may include the user's level and the user's movement attribute. The user's level may be a gold user or a silver user. The user's movement attribute may be the user's movement speed or a movement track. The PCF determines the policy to be used based on the user information and the LADN name, and sends this policy to the SMF. For example, when a gold user accesses LADNN 1 using a LADN PDU session, a type-1 policy is used. In other words, when RAN resources are maintained and the UPF receives downlink data of the LADN PDU session, the UPF buffers the downlink data. For another example, the SMF determines the policy to be used based on information about the LADN name. For example, a type-2 policy is used for a LADN PDU session to access LADNN 2. In other words, RAN resources are maintained, the UPF receives downlink data of the LADN PDU session, and the UPF discards the downlink data.

In some embodiments of the present application, in the process of establishing a session, the SMF obtains a policy from the PCF. This policy is configured for the SMF in a local configuration manner.

In the session establishment process, the detailed implementation process in which the SMF obtains the policy from the PCF is as follows.

Step 1. The UE transmits a session establishment request to the AMF through the RAN. Here, the session establishment request may carry the LADNN and session ID of the LADN PDU session.

Step 2. The AMF selects an SMF from among a plurality of SMFs based on information such as LADNN and subscription data, and forwards the session establishment request to the SMF.

Step 3. The SMF sends a build request to the PCF. Here, the establishment request selectively includes the user's LADNN and mobility properties, and the establishment request may include the LADNN as a PDU-Connect Accessing Network (CAN) session establishment request.

Step 4. The PCF generates policy information and returns a session establishment response to the SMF. Here, the session establishment response carries policy information; For example, the session establishment response may be a PDU-CAN session establishment response.

The PCF may generate policy information based on subscription data (user's level and subscribed LADNN information, etc.), or may generate policy information based on the LADNN loaded in the SMF in step 3, or in step 3 Silly may generate policy information based on the user's movement attribute. Example 1: When the UE is a gold user and the UE connects to LADNN 1, the PCF creates a type-1 policy. Example 2: If the UE is a silver user, the PCF creates a type-2 policy. Example 3: When the UE connects to LADNN 2, the PCF creates a type-3 policy. Example 4: If the UE connects to LADNN 3 and the user's movement speed is relatively slow, the PCF creates a type-4 policy.

The policy information may be a specific policy or may be a policy index. If the policy information is a policy index, the SMF obtains the policy index from the PCF, and then obtains a specific policy to be used through mapping between the policy index and the policy.

In some embodiments of the present application, in an application scenario in which the state of the UE is connected, or in an application scenario in which the state of the UE is connected and the state of the LADN PDU session is active, the UE moves and is handed over, the UE In the handover (HO) procedure of, the session management for the LADN PDU session is described as an example:

The SMF obtains the location information of the UE and determines whether the UE is in the SA of the LADN. When the UE is in the SA of the LADN, the HO procedure of the UE is normally performed. If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. An example is provided below.

If the policy is a type-1 policy, the SMF stops data transmission of the LADN PDU session based on the type-1 policy, that is, RAN resources and UPF resources for the LADN PDU session are maintained, and the UPF sends downlink data. Upon reception, the UPF may buffer or discard the downlink data.

If the policy is a type-2 policy, the SMF triggers a LADN PDU session to enter the first state based on the type-2 policy, in other words, the RAN resource is released while the UPF resource is maintained, and the UPF is downlink When receiving data, the UPF may buffer or discard the downlink data.

If the policy is a type-3 policy, the SMF triggers the LADN PDU session to enter the second state based on the type-3 policy, in other words, the RAN resource is released while the UPF resource is maintained, and the SMF is downlink Upon receiving the data notification, the SMF does not trigger the LADN PDU session to enter the active state.

When the policy is a type-4 policy, the SMF releases the LADN PDU session based on the type-4 policy, that is, releases the RAN resource, the UPF resource, and the SMF resource.

If the SMF uses the type-1 policy, the location of the UE may change, so if the SMF later determines that the UE is in the SA of the LADN, the SMF stops using the type-1 policy, and the data of the LADN PDU session It should be noted that it restores the transfer. In the following two cases, the SMF uses the policy to stop. Case 1: If the UE determines that it is in the SA of the LADN, the SMF stops using this policy and recovers the data transmission of the LADN PDU session. Case 2: When the LADN PDU session is initiated to enter the inactive state, the SMF stops using the Type-1 policy. That the SMF initiates a LADN PDU session to enter the deactivated state may be specifically implemented in a UE context release procedure initiated by AMF or RAN, or a session initiated by UE, RAN, SMF, AMF, or PCF It can be implemented in the deactivation procedure.

In the process of entering the LADN PDU session inactive state, it should be additionally noted that the SMF can manage the LADN PDU session based on the policy. Specifically, the SMF determines whether to use the policy to manage the session based on whether the UE is in the SA of the LADN. If the UE is in the SA of the LADN, when the SMF receives the downlink data notification, the SMF triggers the LADN PDU session to enter the active state. If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. For example, if the policy is a type-2 policy, the SMF initiates a LADN PDU session to enter the first state. In other words, the UPF buffers or discards downlink data when receiving downlink data. Alternatively, if the policy is a type-3 policy, the SMF initiates a LADN PDU session to enter the second state. In other words, when receiving the downlink data notification, the SMF does not trigger the LADN PDU session to enter the active state. Alternatively, if the policy is a type-4 policy, the SMF may release the LADN PDU session.

In some embodiments of the present application, if the UE is not in the SA of the LADN, the SMF network element may additionally perform the following session management solution:

Solution 1: SMF network element activates the timer and informs the UPF network element to buffer or discard downlink data before the timer expires; When the UPF network element receives downlink data after the timer expires, the UPF network element transmits a downlink data notification to the SMF network element so that the SMF network element can trigger the LADN PDU session to enter the active state. do.

Solution 2: The SMF network element activates the timer and informs the UPF network element to buffer or discard the downlink data when the UPF network element receives the downlink data. Before the timer expires, when receiving a downlink data notification from the UPF network element, the SMF network element does not trigger the LADN PDU session to enter the active state. After the timer expires, when receiving a downlink data notification from the UPF network element, the SMF network element triggers a LADN PDU session to enter the active state.

In the above two solutions, after the timer expires, when the SMF network element initiates a LADN PDU session to enter the active state, if the SMF network element finds that the UE is still outside the SA of the LADN, the SMF network element Reactivate the timer; Otherwise, it should be noted that the SMF network element sets the timer to zero.

It should be further noted that in the above two solutions, the duration of the timer is less than the duration of periodic location updates. The duration of periodic location update is set by the AMF network element. The duration of the periodic location update may be transmitted to the SMF network element by the AMF network element during the session establishment process. Specifically, the AMF sends a session management request (SM Request) containing the duration of periodic location update to the SMF.

It should be noted that in the above two solutions, in the case where the duration of the timer is greater than or equal to the duration of periodic location update, the AMF network element acquires the location information of the UE in the periodic location update process. It is to notify the SMF network element of the location information of the UE. The SMF network element determines whether the UE is in the SA of the LADN. If the UE is in the SA of LADN, the SMF sets the timer to zero. If the UE is not in the SA of the LADN, the SMF reactivates the timer.

In some embodiments of the present application, in an application scenario in which the state of the UE is connected and the state of the LADN PDU session is inactive, in the process of entering the HO procedure or the LADN PDU session inactive state, session management for the LADN PDU session It will be described with an example.

(1) In a procedure in which the LADN PDU session enters the inactive state, the SMF processes the LADN PDU session based on the policy.

(2) In the HO procedure, the SMF determines whether the UE is in the SA of the LADN. When the UE is in the SA of LADN, the SMF maintains the inactive state of the LADN PDU session. If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. For example, if the policy is a type-2 policy, the SMF initiates a LADN PDU session to enter the first state. In other words, when the UPF receives downlink data, it buffers or discards the downlink data. Alternatively, if the policy is a type-3 policy, the SMF initiates a LADN PDU session to enter the second state. In other words, when receiving the downlink data notification, the SMF does not trigger the LADN PDU session to enter the active state. Alternatively, if the policy is a type-4 policy, the SMF may release the LADN PDU session.

When the SMF subscribes to a notification message from the AMF indicating whether the UE is not in the SA of the LADN, in the HO procedure, the SMF may process the LADN PDU session in the following embodiment. It should be noted that when the SMF receives the notification message from the AMF, the SMF processes the LADN PDU session based on the policy.

Since the UE is in a connected state, the SMF can always obtain the location information of the UE using the AMF. Accordingly, the SMF can process the LADN PDU session in the manner of (1) or (2). When the LADN PDU session is in an inactive state, the UPF receives downlink data and processes the downlink data based on a method for processing the LADN PDU session as (1) or (2). Specifically, when the policy is a type-2 policy, UPF downlink data is buffered or discarded. When the policy is a type-3 policy, the UPF transmits a downlink data notification to the SMF, and the SMF maintains a deactivated state of the session when receiving the downlink data notification.

In some embodiments of the present application, in an application scenario in which the state of the UE is idle because the LADN PDU session is in an inactive state, when downlink data of the LADN PDU session arrives, session management for the LADN PDU session will be described as an example. do.

Case 1: The UE enters the idle state, the LADN PDU session is processed using the type-2 policy, and the UPF buffers or discards the downlink data.

Case 2: When the UE enters the idle state and the LADN PDU session is processed using the type-3 policy, the SMF receives the downlink data notification and does not trigger the LADN PDU session to enter the active state.

Case 3: The UE enters an idle state, and the SMF does not use the aforementioned policy. When the SMF receives the downlink data notification, the SMF triggers the AMF to call the UE. The UE initiates a service request procedure in response to the call. In the service request procedure, the RAN additionally carries location information, and the RAN side tunnel information is transmitted to the SMF through the AMF. The SMF determines whether the UE is in the LADN's SA based on the location information and the LADN's SA. The UE is in the SA of the LADN, and the SMF performs a subsequent step of the service request procedure. If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. The selected policy type includes a type-2 policy, a type-3 policy, or a type-4 policy. .

In this embodiment of the present application, the SMF stops data transmission of the LADN PDU session of the LADN, and the SMF network element maintains the resources of the LADN PDU session, the SMF network element activates the release timer, and the SMF of the LADN It should be noted that the data transmission of the LADN PDU session is stopped, and the SMF network element includes maintaining the resources of the LADN PDU session before the release timer expires. When the release timer expires, if the SMF finds that the UE is outside the SA of the LADN, the SMF network element is triggered to release the LADN PDU session; Or, if the SMF finds that the UE is in the SA of the LADN, the SMF network element sets the release timer to zero. When the UE is in the idle state, not only the SMF network element activates the release timer, but also the UE side activates the release timer. When the release timer expires, if the UE is still outside the SA of the LADN, the UE releases the resources for the LADN PDU session on the UE, and the SMF network element is the resource for the LADN PDU session on the network element of the core network. Release.

Three different examples for this application will be described below as an example. Embodiment 1: When the UE is in the connected state and the LADN PDU session is in the active state, the LADN PDU session is processed using a type-1 policy, a type-2 policy, a type-3 policy, or a type-4 policy. Embodiment 2: When the UE is in the connected state and the LADN PDU session is in the inactive state, the LADN PDU session is processed using a type-2 policy, a type-3 policy, or a type-4 policy. Embodiment 3: When the UE is in the idle state, the LADN PDU session is processed in a specific manner.

First, referring to the following Example 1,

As shown in FIG. 4, this embodiment describes a case in which a UE moves and is handed over when the LADN PDU session is in an active state, and the LADN PDU session is processed in the HO procedure. 4 is a flowchart schematically illustrating an interaction between a plurality of network elements in a session management method in a handover procedure according to an embodiment of the present application. The specific procedure includes the following steps.

401. The UE moves and is handed over to the target RAN, and the target RAN transmits a path switching request (N2 path switching request) containing a list of sessions that need to be switched to the AMF.

402. The AMF sends an N11 message to the SMF corresponding to the list. Here, the N11 message carries tunnel information on the target RAN side and location information on the UE. Tunnel information is included in N2 Session Management (SM) information. For example, the tunnel information on the target RAN side may include an IP address of the RAN and a tunnel endpoint identifier (RAN TEID) on the RAN side.

In the case of a session not included in the above list, for example, a session that has not been switched over or a session in an inactive state, the AMF sends an N11 message to the corresponding SMF to notify the SMF of a session switching failure or location update.

In some embodiments of the present application, the SMF may additionally subscribe to the location information of the UE from the AMF. Accordingly, when the AMF finds that the location of the UE has changed, the AMF transmits an N11 message containing the location of the UE to the SMF to notify the SMF of the location information of the UE.

403. The SMF processes the state of the LADN PDU session, the SA of the LADN, and the LADN PDU session based on the location of the UE. There are several specific treatment examples:

(1) When the LADN PDU session is in the active state and the UE is in the SA of the LADN, the SMF performs the following HO procedure of the UE. Specifically, the following steps are included.

Step 1. The SMF transmits a user plane path change request carrying the tunnel information of the target RAN to the UPF, and updates the RAN side tunnel information stored in the UPF.

Step 2. The UPF returns a user plane path change response.

Step 3. The SMF returns an N11 message acknowledgment (N11 message ACK) to the AMF.

Step 4. The AMF sends a path switching request response to the target RAN.

Step 5. The target RAN transmits a resource release instruction to the source RAN.

(2) When the LADN PDU session is in the active state and the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. The processing method depends on the policy type.

(a) Type-1 policy

When the SMF stops data transmission of the LADN PDU session, that is, maintains RAN resources and UPF resources, and receives downlink data, the UPF may buffer or discard the downlink data.

The concrete implementation may be as follows.

Step 1. The SMF sends a notification message to the UPF to notify the UPF not to transmit the downlink data to the RAN, but when the UPF receives the downlink data, the downlink data is buffered or discarded.

Step 2. Optionally, the UPF returns a notification response.

(b) Type-2 policy

When the SMF triggers the LADN PDU session to enter the first state, in other words, releases the RAN resource and maintains the UPF resource, and the UPF receives downlink data, the UPF buffers or discards the downlink data. I can.

The concrete implementation may be as follows.

Step 1. The SMF sends a notification message to the UPF to notify the UPF to buffer or discard the downlink data when the UPF receives the downlink data.

Step 2. Optionally, the UPF returns a notification response.

Step 3. The SMF sends a release command to the RAN through the AMF to request the RAN to release the radio resource.

Step 4. After receiving the release command, the RAN is triggered to release the radio connection between the RAN and the UE.

Step 5. The RAN returns completion of the release to the SMF through the AMF.

When receiving downlink data of an LADN PDU session, the UPF performs the following steps.

Step 1. UPF downlink data is buffered or discarded.

(c) Type-3 policy

When the SMF triggers the LADN PDU session to enter the second state, that is, releases the RAN resource and maintains the UPF resource, and receives downlink data, the UPF transmits a downlink data notification to the SMF, and the SMF Do not trigger a session to enter the active state.

The concrete implementation may be as follows.

Step 1. The SMF sends a release command to the RAN via the AMF to request the RAN to release the radio resource.

Step 2. After receiving the release command, the RAN is triggered to release the radio connection between the RAN and the UE.

Step 3. The RAN returns completion of the release to the SMF through the AMF.

When receiving downlink data of an LADN PDU session, the UPF performs the following steps.

Step 1. The UPF transmits a downlink data notification message carrying the session ID to the SMF.

Step 2. When receiving the downlink data notification, the SMF does not trigger the LADN PDU session to enter the active state. In other words, the SMF maintains the inactive state of the LADN PDU session.

(d) Type-4 policy

The LADN PDU session is released by triggering by the SMF. In other words, the SMF releases the RAN resource, releases the UPF resource, and triggers the SMF resource.

A specific embodiment may be as follows.

Step 1. The SMF sends a session release request (N4 session release request) carrying the N4 session ID to the UPF in order to request the UPF to release the session resource corresponding to the N4 session ID.

Step 2. UPF returns a session release response.

Step 3. The SMF sends a release command to the RAN through the AMF to request the RAN to release the radio resource.

Step 4. After receiving the release command, trigger the RAN to release the radio connection between the RAN and the UE.

Step 5. The RAN returns completion of the release to the SMF through the AMF.

Steps 3 to 5 described above are, when the RAN needs to transmit uplink data to the UPF, the UPF cannot process the uplink data, so the UPF returns error information, and the RAN responds to the error information. It should be noted that it can be replaced by a step of releasing session resources for the RAN.

It should be noted that when the LADN PDU session is processed using the type-1 policy, the SMF may stop processing the LADN PDU session using the type-1 policy. Specifically, there may be the following two implementation cases.

Case 1. When the UE moves to the SA of LADN, the SMF stops processing the type-1 policy for the LADN PDU session. The specific steps are as follows.

Step 1. The UE moves (continued) and is handed over to the target RAN, and the target RAN transmits a path switching request to the AMF.

Step 2. Based on the location of the UE and the SA of the LADN, when it is determined that the UE is in the SA of the LADN, the SMF stops processing the type-1 policy for the LADN PDU session to recover the data transmission process of the LADN PDU session. do.

Case 2: When the LADN PDU session enters the inactive state, the type-1 policy processing for the LADN PDU session is stopped. To determine whether the SMF will use the policy based on the location of the UE and the SA of the LADN, it determines whether the UE is in the SA of the LADN.

The reason why the LADN PDU session enters the inactive state is that the UE is in an idle state, for example, a UE context release procedure (UE context release in the AN procedure) for an AN initiated by the RAN or AMF, or the UE, RAN, SMF, It may be to enter the session deactivation procedure initiated by the AMF or PCF.

Taking the UE context release procedure on the RAN initiated by AMF as an example, as shown in FIG. 5, FIG. 5 schematically illustrates the interaction between a plurality of network elements in a scenario for releasing RAN resources according to an embodiment of the present application. This is the flow chart shown. The detailed procedure is as follows.

501. The AMF transmits a session deactivation request containing the UE's session ID and location information to the SMF.

502. The SMF determines whether the UE is in the SA of the LADN, based on the location information of the UE and the SA of the LADN.

If the UE is in the SA of the LADN, the SMF performs subsequent steps 503 to 508.

If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. For example, this policy is the following type-2 policy, or type-3 policy, or type-4 policy.

Type-2 policy: When the SMF triggers the LADN PDU session to enter the first state, the session change request sent by the SMF to the UPF in step 503 is additionally, the downlink of the LADN PDU session when the UPF receives downlink data Used to notify the UPF to buffer or discard link data.

Type-3 policy: SMF triggers a LADN PDU session to enter the second state. When the SMF receives a downlink data notification from the UPF, the SMF does not trigger a session to enter the active state.

Type-4 policy: In order to trigger UPF to release session-related context such as tunnel information, session ID, and QoS corresponding to the RAN side, SMF triggers to release the LADN PDU session Then, the session change request of step 503 should be replaced with the session release request, and the session change response of step 504 should be replaced with the session release response.

Step 503. The SMF sends a session change request to the UPF to trigger the UPF to delete the tunnel information of the RAN from the UPF.

Step 504. The UPF returns a session change response.

Step 505. The SMF sends a session deactivation response to the AMF.

Step 506. AMF sends a UE context release request to the RAN to trigger the RAN to initiate UE context release.

Step 507. The RAN initiates release of the radio connection between the RAN and the UE.

Step 508. The RAN sends UE context release completion to the AMF.

It should be noted that the SMF stores information about the SA of the LADN, and information about the SA may be transmitted from the AMF or PCF to the SMF during the session establishment process. A specific embodiment may include the following two methods, but is not limited thereto.

Method 1: In the session establishment process, the AMF transmits the SA of the LADN to the SMF.

Step 1. The UE transmits a session establishment request carrying the LADNN and the session ID to the AMF.

Step 2. The AMF selects an SMF based on information such as LADNN and subscription data, forwards a session establishment request to the SMF, and transmits the LADN SA parameter to the SMF.

Step 3. The SMF stores information on the SA of the LADN.

Method 2: In the session establishment process, the SMF obtaining information on the SA of the LADN from the PCF may include the following steps.

Step 1. The UE transmits a session establishment request containing the LADNN and the session ID to the AMF.

Step 2. The AMF selects the SMF based on information such as LADNN and subscription data, and forwards the session establishment request to the SMF.

Step 3. The SMF sends an establishment request, such as a PDU-CAN session establishment request, to the PCF. Here, the construction request carries LADNN.

Step 4. The PCF returns an establishment response, such as a PDU-CAN session establishment response, to the SMF. Here, the establishment response carries the SA of LADN.

In the above-described schemes 1 and 2, the SMF stores information on the SA of the LADN.

It can be seen from the above exemplary description of Embodiment 1, that when the UE is in the connected state, the SMF processes the LADN PDU session in the active state based on the policy, or, for example, stops data transmission of the LADN PDU session. Or by activating the LADN PDU session to enter the first state, or activating the LADN PDU session to enter the second state, or by releasing the session, the UE enters and exits the SA of the LADN due to frequent movements. The high signaling overhead can be avoided.

Next, referring to the following Example 2,

This embodiment describes a method in which the SMF processes the LADN PDU session in the following three cases when the UE is in the connected state and the LADN PDU session is in the inactive state. (1) When the LADN PDU session enters the inactive state, the SMF processes the LADN PDU session using the policy; (2) when the LADN PDU session is in an inactive state and the UE moves and is handed over, the SMF processes the LADN PDU session using the policy in the HO procedure; (3) When the LAND PDU session is in an inactive state, when downlink data reaches the UPF, the SMF processes the LADN PDU session using the policy.

(1) Procedure for LADN PDU session to enter inactive state

When the LADN PDU session enters the inactive state, the LADN PDU session is stopped to be processed using the type-1 policy. In order for the SMF to determine the type of policy to be used based on the location of the UE and the SA of the LADN, it determines whether the UE is in the SA of the LADN. The reason why the LADN PDU session enters the inactive state is that the UE is in an idle state, e.g., a UE context release procedure for an AN initiated by RAN or AMF (UE context release in an AN procedure), or a UE, RAN, SMF, It may be to enter the session deactivation procedure initiated by the AMF or PCF.

(2) HO procedure

Referring to FIG. 6, FIG. 6 is a flowchart schematically illustrating another interaction between a plurality of network elements of a session management method in a handover procedure according to an embodiment of the present application. The detailed procedure is as follows.

601. The UE moves and is handed over to the target RAN, and transmits a path switching request (N2 path switching request) containing a list of sessions in which the target RAN needs to be switched to the AMF.

602. The AMF sends an N11 message to the SMF corresponding to the list. Here, the N11 message carries tunnel information on the target RAN side and location information on the UE. Tunnel information is included in N2 Session Management (SM) information. For example, the tunnel information on the target RAN side may be an IP address of the RAN and a tunnel endpoint identifier (RAN TEID) on the RAN side.

In the case of a session not in the above list, that is, an LADN PDU session in an inactive state, the AMF also transmits N11 message information carrying the location of the UE to the SMF.

Note that in the case of a session not in the above list, that is, a LADN PDU session in an inactive state, there is another processing method in which the AMF determines whether the UE is outside the SA of the LADN based on the location information of the UE and the SA of the LADN. Should be. If the UE is outside the SA of the LADN, the AMF sends an N11 message to the SMF corresponding to the LADN PDU session to notify the SMF to process the LADN PDU session based on the policy.

603. The SMF processes the LADN PDU session based on the location of the UE and the SA of the LADN. The specific processing is as follows.

(1) When the UE is in the SA of the LADN, the SMF maintains the inactive state of the LADN PDU session.

(2) If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. The processing method differs according to different policy types, that is, type-2 policy, type-3 policy, and type-4 policy.

When the LADN PDU session is in the inactive state, when the UPF receives the downlink data of the LADN PDU session, this processing method is the type of policy used by the SMF for the LADN PDU session when the LADN PDU session enters the inactive state. It should be noted that it is related to.

When the type-2 policy is used, the UPF discards or buffers the received downlink data.

When the type-3 policy is used, the UPF sends a downlink data notification carrying a session ID to the SMF, and the SMF receives the downlink data notification and does not trigger a session to enter the active state.

When the type-4 policy is used, the above-described case does not exist. In other words, the UPF does not receive downlink data.

If none of the above-described policies are used, the following steps are performed.

Step 1. The UPF transmits a downlink data notification carrying the session ID to the SMF.

Step 2. The SMF transmits an N11 message containing the UPF's session ID and tunnel information to the AMF.

Step 3. The AMF determines that the UE is in a connected state, and the AMF transmits an N2 request message carrying the tunnel information of the UPF to the RAN.

Step 4. The RAN initiates a process of establishing a radio connection between the RAN and the UE.

Step 5. The RAN transmits an N2 request ACK message carrying tunnel information of the RAN to the AMF.

Step 6. The AMF transmits the N11 message carrying the tunnel information of the RAN to the SMF.

Step 7. The SMF transmits a user plane path change request carrying the tunnel information of the RAN to the UPF.

Step 8. UPF returns a user plane path change response.

Step 9. The SMF returns an N11 message acknowledgment to the AMF.

It can be seen from the above-described exemplary description of Embodiment 2, that when the UE is in the connected state and the LADN PDU session enters the inactive state or the UE is handed over, the SMF is the LADN PDU in the inactive state based on the policy. Either process the session, activate the LADN PDU session to enter the first state, for example, or activate the LADN PDU session to enter the second state, or release the session. In this way, the LADN PDU session can be appropriately handled so that the UE can avoid high signaling overhead due to frequent movements entering and leaving the SA of the LADN.

Finally, referring to the following Example 3,

This embodiment describes a method of processing a LADN PDU session when a UE is in an idle state during a call triggered by a network side. In other words, when downlink data arrives, this processing scheme is implemented to reduce signaling overhead due to persistent calls to the UE.

Referring to FIG. 7, FIG. 7 is a flowchart schematically illustrating interactions between a plurality of network elements of a session management method in a paging procedure according to an embodiment of the present application. Specifically, the following procedures are included.

(Call procedure)

Step 701. The UPF receives downlink data of the LADN PDU session.

Step 702. The UPF transmits a downlink data notification carrying the session ID to the SMF.

Step 703. The SMF transmits the N11 message carrying the Subscriber Permanent Identifier (SUPI), the session ID, and the N2 SM information to the AMF. Here, the N2 SM information includes a QoS parameter of a session and tunnel information of the UPF side.

Step 704. If it is determined that the UE is in the idle state, the AMF triggers a procedure for calling the UE and sends a call message to the RAN.

Step 705. The RAN sends a paging message to the UE.

(Service Request Procedure)

The called UE initiates the following service request procedure to respond to the calling procedure.

Step 711. The UE transmits a radio resource control (RRC) message carrying a mobility management (MM) NAS service request to the RAN.

Step 712. The RAN transmits an N2 message containing the MM NAS service request and the location information of the UE to the AMF.

Step 713. The AMF transmits an N2 request carrying the MM NAS service acceptance message and the session ID to the RAN.

Step 714. The RAN initiates establishment of a radio connection between the RAN and the UE.

Step 715. The RAN transmits an N2 request acknowledgment (request ACK) containing the tunnel information of the RAN and the location information of the UE to the AMF.

Step 716. The AMF transmits, to the SMF, an N11 message containing the tunnel information of the RAN and the location information of the UE.

Step 717. Based on the location information of the UE and the SA of the LADN, the SMF determines whether the UE is in the SA of the LADN. If the UE is in the SA of the LADN, the SMF performs subsequent steps 718 and 719. If the UE is not in the SA of the LADN, the SMF processes the LADN PDU session based on the policy. Specifically, the SMF may perform a type-2 policy, a type-3 policy, or a type-4 policy.

Step 718. The SMF transmits a user plane path change request (N4 session change request) carrying tunnel information of the RAN to the UPF.

Step 719. The UPF returns a user plane path change response (N4 session change response) to the SMF.

Step 720. The SMF returns an N11 message acknowledgment (message ACK) to the AMF.

When the SMF subscribes to notification information indicating that the UE is outside the SA of the LADN from the AMF, steps 713 to 720 in the above-described service request procedure include the AMF based on the location information of the UE and the SA of the LADN, the UE It should be noted that may be replaced by an embodiment that determines whether or not is outside the SA of the LADN. If the UE is outside the SA of the LADN, the AMF sends notification information to the SMF to notify the SMF to process the LADN PDU session based on the policy.

It can be seen from the above-described exemplary description of Embodiment 3, when the UE is in an idle state, if the downlink data of the LADN PDU session needs to be transmitted, the LADN PDU session in the present application is released for the UE. It is possible to reduce signaling overhead due to continuous calls.

It should be noted that for the sake of simplicity, the foregoing method embodiments have been shown as a series of operations. However, according to the present application, since some steps may be performed in a different order or may be performed simultaneously, those skilled in the art should understand that the present application is not limited to the described order of operations. It will be understood by those skilled in the art that all of the embodiments described herein belong to preferred embodiments, and operations and modules in the embodiments are not necessarily required in the present application.

Hereinafter, in order to better implement the above-described solution of the embodiment of the present application, a related apparatus for implementing the above-described solution is additionally provided.

Referring to Figure 8a, the embodiment of the present application provides an SMF network element 800. The SMF network element 800 may include a condition learning module 801 and a processing module 802.

The condition learning module 801 is configured to learn whether the first condition is satisfied. The first condition includes that the location of the first user equipment (UE) is outside the service area (SA) of the local area data network (LADN).

When the first condition is satisfied, the processing module 802 is configured to stop data transmission of an LADN packet data unit (PDU) session of the LADN and maintain resources of the LADN PDU session.

In some other embodiments of the present application, the condition learning module 801 is configured to learn whether the first condition is satisfied. The first condition includes that the location of the first user equipment (UE) is outside the service area (SA) of the local area data network (LADN).

If the first condition is satisfied, the processing module 802 stops data transmission of the LADN packet data unit (PDU) session of the LADN and maintains the resources of the LADN PDU session based on the policy; Or it is configured to release the LADN PDU session. This policy is associated with at least one of the user information of the UE and the identification information of the LADN.

In some embodiments of the present application, the conditional learning module specifically obtains a first location of the UE and, based on the first location of the UE, determines whether the UE is outside the SA of the LADN; Or, it is configured to obtain a notification message including whether the UE is outside the SA of the LADN, and learn whether the UE is outside the SA of the LADN based on the notification message.

In some embodiments of the present application, referring to FIG. 8B, the SMF network element 800 further includes a state acquisition module 803 configured to acquire the state of the LADN PDU session.

The first condition further includes that the LADN PDU session is in an active state.

In some embodiments of the present application, the processing module 802 specifically notifies a user plane function (UPF) network element to buffer or discard the received downlink data; Alternatively, when the SMF network element receives a downlink data notification from the UPF network element, it is configured to maintain the state of the LADN PDU session in an inactive state.

In some embodiments of the present application, the processing module 802 is specifically configured to activate the timer and notify the UPF network element to buffer or discard received downlink data before the timer expires.

The processing module 802 additionally receives a downlink data notification from the UPF network element when the UPF network element receives downlink data after the timer expires; It is configured to trigger establishment of a transmission resource of an LADN PDU session in response to the received downlink data notification.

In some embodiments of the present application, the processing module 802 specifically activates the timer and informs the UPF network element to buffer or discard the received downlink data when the UPF network element receives the downlink data. Is composed.

The processing module 802 is further configured to notify the UPF network element to send a downlink data notification to the SMF network element when the UPF network element receives the downlink data after the timer expires.

In some embodiments of the present application, the processing module 802 specifically activates the timer, and before the timer expires, deactivates the state of the LADN PDU session when the SMF network element receives the downlink data notification from the UPF network element. It is configured to remain in the state.

The processing module 802 is further configured to trigger establishment of the transmission resource of the LADN PDU session upon receiving the downlink data notification from the UPF network element after the timer expires.

In some embodiments of the present application, the processing module 802 specifically maintains radio access network (RAN) resources and UPF network element resources for the LADN PDU session; Or release RAN resources for the LADN PDU session, and maintain UPF network element resources for the LADN PDU session; Alternatively, RAN resources and UPF network element resources for the LADN PDU session are released, and the SMF network element is configured to maintain SMF network element resources for the LADN PDU session.

Further, in some embodiments of the present application, the processing module 802 specifically, via an AMF network element, notifies the RAN to release the RAN resource; Or, by notifying the UPF network element to release the UPF network element resource, when the RAN transmits uplink data to the UPF network element, the UPF network element returns error information to the RAN, and the RAN returns the RAN resource based on the error information. Is configured to release.

In some embodiments of the present application, the condition learning module 801 is additionally configured to learn whether a second condition is satisfied. The second condition includes that the second location obtained after the UE moves is in the SA of the LADN.

The processing module 802 is further configured to allow the SMF network element to recover the data transmission of the LADN PDU session when the second condition is satisfied. The second condition includes that the location of the second UE is in the SA of the LADN.

In some embodiments of the present application, referring to FIG. 8C, the SMF network element 800 obtains a policy from a local policy of the SMF network element, or obtains a policy configured to obtain a policy from a policy control function (PCF) network element. It further includes a module 804.

In some embodiments of the present application, the condition learning module 801 specifically, when the UE is in an idle state, to receive a downlink data notification from the UPF network element, based on the downlink data notification, to call the UE Trigger an access and mobility management function (AMF) network element; When the UE initiates a service request in response to the call, obtains the first location of the UE from the RAN using the AMF network element; Or subscribes to the location information of the UE from the AMF network element, and is configured to receive the first location from the AMF network element.

In some embodiments of the present application, referring to FIG. 8D, the SMF network element 800 further includes an SA information obtaining module 805 configured to obtain information about the SA of LADN from a PCF network element or an AMF network element. .

Note that the content such as information interaction between the module/unit of the above-described device and the execution process is based on the same concept as the content of the method embodiment of the present application, and brings the same technical effect as the technical effect of the method embodiment of the present application. Should be. For details, refer to the description of the foregoing method embodiment of the present application, and details are not described again here.

The embodiment of the present application further provides a computer storage medium. The computer storage medium stores a program, and the program performs some or all of the steps described in the above-described method embodiments.

Next, an embodiment of another SMF network element provided in the present application will be described. 9, the SMF network element 900,

It includes a receiver 901, a transmitter 902, a processor 903, and a memory 904 (the SMF network element 900 may have one or more processors 903, and in FIG. 9, there is one processor. Example is used). In some embodiments of the present application, the receiver 901, the transmitter 902, the processor 903, and the memory 904 may be connected using a bus or may be connected in other ways. An example in which the receiver 901, the transmitter 902, the processor 903, and the memory 904 are connected using a bus is used in FIG. 9.

Memory 904 may include read-only memory and random access memory, and provides instructions and data for processor 903. Some of the memories 904 may further include non-volatile random access memory (NVRAM). The memory 904 stores the operating system and operation instructions, executable modules or data structures, subsets thereof, or an extended set thereof. The operation instruction may implement various operations, including various operation instructions. The operating system may include various system programs to implement various basic services and handle hardware-based tasks.

The processor 903 controls the operation of the SMF network element. The processor 903 may also be referred to as a central processing unit (CPU). In a specific application, all components of the SMF network element are connected together using a bus system. In addition to the data bus, the bus system may further include a power bus, a control bus, and a status signal bus. However, for clarity, various types of buses are indicated as bus systems in the drawings.

The session management method disclosed in the above-described embodiment of the present application may be applied to the processor 903 or may be implemented by the processor 903. The processor 903 may be an integrated circuit chip and has signal processing capability. In the implementation process, the steps in the above-described method may be completed using an integrated logic circuit of hardware in the processor 903 or using instructions in the form of software. The processor 903 is a general-purpose processor, digital signal processing (DSP), application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, It may be a discrete gate or transistor logic device, or a separate hardware component. The processor 903 may implement or perform the session management method, steps, and logical block diagram disclosed in the embodiment of the present application. The general purpose processor may be a microprocessor or the processor may be a conventional processor. The steps of the method disclosed with reference to the embodiments of the present application may be directly performed and completed using a hardware decoding processor, or may be performed and completed using a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium mature in the art such as random access memory, flash memory, read-only memory, programmable ROM, EPROM, or register. The storage medium resides in the memory 904, and the processor 903 reads the information in the memory 904 and combines it with the hardware of the processor to complete the steps of the method described above.

In this embodiment of the present application, the processor 903 is configured to perform the steps of the method embodiment described above.

In addition, it should be noted that the above-described device embodiments are only examples. A unit described as a separate part may or may not be physically separated, and a part marked as a unit may or may not be a physical unit, may lie in one location, or a plurality of networks It can be distributed across units. Some or all modules may be selected according to actual needs to achieve the objectives of the solutions of the embodiments. Further, in the accompanying drawings of the device embodiments provided in the present application, the connection relationship between the modules indicates that the modules have a communication connection with each other, which can in particular be implemented as one or more communication buses or signal cables. Those skilled in the art will be able to understand and implement the embodiments of the present invention without creative efforts.

Based on the description of the above-described embodiment, it is understood that the present application can be implemented using software as well as general hardware required, or using dedicated hardware including a dedicated integrated circuit, a dedicated CPU, a dedicated memory, and a dedicated component. Those skilled in the art will be able to clearly understand. In general, any function that can be performed by a computer program can be easily implemented using corresponding hardware. In addition, a specific hardware structure used to implement the same function may be in various forms, for example, in the form of an analog circuit, a digital circuit, or a dedicated circuit. However, in the case of this application, the software program embodiment is the better embodiment in most cases. Based on this understanding, the technical solution of the present application may be implemented in the form of a software product basically or a part contributing to the prior art. The software product is stored on a readable storage medium such as a floppy disk, a USB flash drive, a removable hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk of a computer, and the session management described in the embodiments of the present application It contains several instructions for instructing a computer device (which may be a personal computer, server, and network device, etc.) to perform the method.

All or part of the above-described embodiments may be implemented using software, hardware, firmware, or any combination thereof. If the embodiment is implemented using software, the embodiment may be fully or partially implemented in the form of a computer program product.

The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, all or partially generated procedures or functions according to the embodiments of the present application. The computer may be a general purpose computer, a dedicated computer, a computer network, or other programmable device. The computer instructions may be stored on a computer-readable storage medium or may be transferred from a computer-readable storage medium to another computer-readable storage medium. For example, computer commands can be sent to websites, computers, servers, or data via wired (coaxial cable, optical fiber, or digital subscriber line (DSL), etc.) or wireless (infrared, wireless, or microwave, etc.) method. It can be transferred from the center to another website, computer, server, or data center. Computer-readable storage media may be any available media that can be stored in a computer or a data storage device such as a server or data center incorporating one or more available media. The usable medium may be a magnetic medium (such as a soft disk, a hard disk, or a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

Claims (31)

As a session management method,
Learning whether a first condition is satisfied by a session management function (SMF) network element (201)-The first condition is that the first location of the user equipment (UE) is a local area data network (local area data network, LADN) includes the outside of the service area (service area, SA) -; And
When the first condition is satisfied, the SMF network element activates a release timer, and the SMF network element stops data transmission of an LADN packet data unit (PDU) session of the LADN (202), Maintaining, by the SMF network element, the resources of the LADN PDU session before the release timer expires; And
When the release timer expires, in response to the SMF finding that the UE is outside the SA of the LADN, triggering the SMF network element to release the LADN PDU session
Session management method comprising a. The method of claim 1,
Learning whether the first condition is satisfied by the session management function (SMF) network element,
The SMF network element obtaining a first location of the UE, and determining, based on the first location of the UE, whether the UE is outside the SA of the LADN
Including a session management method. The method of claim 1,
Learning whether the first condition is satisfied by the session management function (SMF) network element,
Acquiring a notification message including whether the SMF network element is outside the SA of the LADN, and learning whether the UE is outside the SA of the LADN based on the notification message
Including a session management method. The method of claim 1,
The session management method,
The SMF network element obtaining the state of the LADN PDU session
Including more,
The first condition further comprises that the LADN PDU session is in an active state. The method of claim 1,
Stopping data transmission of the LADN PDU session of the local area data network (LADN),
The SMF network element notifies a user plane function (UPF) network element to buffer or discard received downlink data
Including a session management method. The method of claim 5,
The SMF network element notifies a user plane function (UPF) network element to buffer or discard received downlink data,
The SMF network element notifies the UPF network element to activate a timer and buffer or discard the received downlink data before the timer expires.
Includes;
The session management method,
When the UPF network element receives downlink data after the timer expires, receiving, by the SMF network element, a downlink data notification from the UPF network element; And
Triggering, by the SMF network element, establishment of transmission resources of the LADN PDU session in response to the received downlink data notification
Session management method further comprising a. The method of claim 5,
The SMF network element notifies a user plane function (UPF) network element to buffer or discard received downlink data,
Informing the UPF network element to buffer or discard the received downlink data when the SMF network element activates a timer and the UPF network element receives the downlink data
Includes;
The session management method,
After the timer expires, the SMF network element notifying the UPF network element to transmit a downlink data notification to the SMF network element when the UPF network element receives downlink data
Session management method further comprising a. The method of claim 1,
Stopping data transmission of the LADN PDU session of the local area data network (LADN),
When the SMF network element receives a downlink data notification from a UPF network element, the SMF network element maintains the state of the LADN PDU session in an inactive state.
Including a session management method. The method of claim 8,
When the SMF network element receives a downlink data notification from a UPF network element, the SMF network element maintains the state of the LADN PDU session in an inactive state,
When the SMF network element receives the downlink data notification from the UPF network element, the SMF network element activates a timer, and before the timer expires, the SMF network element indicates the state of the LADN PDU session. Keeping inactive
Includes;
The session management method,
After the timer expires, when the SMF network element receives the downlink data notification from the UPF network element, triggering, by the SMF network element, establishment of transmission resources of the LADN PDU session
Session management method further comprising a. The method of claim 1,
Maintaining the resources of the LADN PDU session,
Maintaining, by the SMF network element, a radio access network (RAN) resource and a UPF network element resource for the LADN PDU session; or
Releasing, by the SMF network element, RAN resources for the LADN PDU session, and maintaining UPF network element resources for the LADN PDU session; or
The SMF network element releases RAN resources and UPF network element resources for the LADN PDU session, and the SMF network element maintains SMF network element resources for the LADN PDU session.
Including a session management method. The method of claim 10,
The SMF network element releases the RAN resource for the LADN PDU session,
The SMF network element notifying the RAN to release the RAN resource through the AMF network element; or
When the RAN transmits uplink data to the UPF network element, the UPF network element returns error information to the RAN, and the RAN can release the RAN resource in response to the error information, the SMF Notifying the UPF network element to release the UPF network element resource by the network element
Including a session management method. The method of claim 1,
Learning whether a second condition is satisfied by the SMF network element-the second condition includes that the second location obtained after the UE moves is in the SA of the LADN; And
When the second condition is satisfied, the SMF network element recovering data transmission of the LADN PDU session
Session management method further comprising a. The method of claim 2,
The SMF network element obtaining the first location of the UE,
When the UE is in an idle state, the SMF network element receives a downlink data notification from a UPF network element, and the SMF network element connects to page the UE in response to the downlink data notification, and Triggering an access and mobility management function (AMF) network element; When the UE initiates a service request in response to the call, the SMF network element obtaining a first location of the UE from the RAN using the AMF network element; or
The SMF network element subscribes to the location information of the UE from the AMF network element, and the SMF network element receives the first location from the AMF network element.
Including a session management method. The method of claim 1,
The SMF network element obtaining information about the SA of the LADN from a policy control function (PCF) network element or an AMF network element
Session management method further comprising a. As a session management function (SMF) network element,
A condition learning module configured to learn whether a first condition is satisfied.- The first condition is that a first location of a user equipment (UE) is a service area of a local area data network (LADN). area, SA) includes outside -; And
When the first condition is satisfied, the SMF network element activates a release timer, stops data transmission of the LADN packet data unit (PDU) session, and before the release timer expires, the Processing module configured to trigger the release of the LADN PDU session in response to the SMF finding that the UE is outside the SA of the LADN when the resource of the LADN PDU session is maintained and the release timer expires
Session Management Function (SMF) network element comprising a. The method of claim 15,
The conditional learning module is specifically configured to acquire a notification message including whether the UE is outside the SA of the LADN, and learn whether the UE is outside the SA of the LADN based on the notification message. Management function (SMF) network element. The method of claim 15,
The processing module is specifically configured to notify a user plane function (UPF) network element to buffer or discard received downlink data. A session management function (SMF) network element. A computer-readable storage medium containing instructions, wherein when the instructions are executed on a computer, the computer performs the method according to any one of claims 1 to 14. A computer program stored in a computer-readable storage medium and containing instructions, wherein when the computer program is executed on a computer, the computer performs the method according to any one of claims 1 to 14. delete delete delete delete delete delete delete delete delete delete delete delete

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